<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>注释和嵌入式CSS</title>
</head>
    <style type="text/css">
    /*给div进行设置，颜色蓝色*/
    div{
        width:500px;/*给div设置宽度 */
        height:800px;
        background-color:royalblue
        }
    </style>
<body>
    <div>方块</div>
</body>
</html>